Carburetor



Sept. 14, I937.

C. O. GROSZ CARBURETOR Filed Aug. 16. 1955 INVENTOR.

Charles I1 Grusz.

ATTORNEYS.

Patented Sept. 14, 1937 UNITED STATES PATENT OFFICE 3 Claims.

The present invention relates to carburetors and the primary object of the invention is to provide a carburetor embodying improved means for efficiently mixing the explosive charge upon both an open and a closed throttle condition of the carburetor.

A further object of the invention resides in the novel arrangement whereby there is an initial mixing of the fuel and air prior to its admixture with the main or primary air supply.

A further object resides in the novel construction of the high speed and the idling needle valve having axial air channels thru which air is drawn for mixing with the fuel prior to passage of this mixture into the fuel delivery passage of the carburetor.

A further object resides in the arrangement of the idling fuel supply whereby explosive fumes may be drawn from the float chamber into the idling fuel supply. A still further and important object resides in the novel arrangement for heating the chamber so as to cause quick and easy vaporization of the fuel therein.

Other objects and advantages of the invention will be apparent from the following detailed description, taken in connection with the accompanying drawing forming a part of this specification and in which drawing:-

Figure 1 is a central vertical section thru the improved carburetor.

Figure 2 is a horizontal section substantially on the line 2--2\of Figure 1.

Figure 3 is a fragmentary section on the line 3-3 of Figure 1.

In the drawing, and wherein like reference characters designate corresponding parts thruout the several views, the carburetor is preferably formed with an upper section A and a lower section B and is preferably formed of a quick heating metal such as aluminum or the like.

The upper. body section A is formed with a fuel delivery passage 5 provided at its upper end with an attaching flange 6 for connection in the usual manner to the intake manifold of an internal combustion engine. Mounted concentrically within the lower portion of the passage 5 is a Venturi tube 1 of an external diameter less than the internal diameter of the passage 5 and having a flaring upper end portion spaced from the inner wall of the passage whereby a passageway is formed both thru and about the tube. The tube 1 may be supported in position by means of two lugs 9 receiving suitable retaining screws l0 as shown in Figure 2. Provided in the upper end portion of the passage 5 is the usual throttle valve II for controlling passage of the main explosive mixture.

Cast integral with one side of the passage 5 is a solid body heating portion I2 which preferably flares outwardly at its lower end as shown more clearly in Figure 2. Formed at the upper end of the heating portion I2 is a hollow extension l3 providing an idling mixing chamber l4 having communication with the passage/5 above the throttle valve H thru the horizontal port or passageway l5. Threaded thru the wall of the extension IS in axial alignment with the port I5 is an idle adjusting screw and air feed needle valve l6 having an axial bore l1 providing an air inlet to the idling mixing chamber l4. A coil spring I8 serves to retain the needle valve 16 in its adjusted position. Extending vertically thru the heating portion I2 is a small idling duct or passageway l9 having its upper end opening into the idling mixing chamber I4.

The lower body section B is formed with a float chamber 20 arranged beneath the heating portion l2 and a passage portion 2| of tubular formation aligning co-axially beneath the tubular passage 5. Opening into the lower end of the passage'portion 2| is a main air intake 22 which may be provided with a choke valve 23.

The upper body section A is secured to the lower body section B by means of two bolts 24 whereby the heating portion I2 forms a cover for the float chamber 20. The lower end of the heating portion I2 is of a size substantially equal to the size of the float chamber 20 and small flanges as at 25 are provided to allow space for the bolts 24 which may be threaded into tapped openings formed in lugs provided one on each side of the float chamber A thin rim or body gasket 26 may be provided between the upper and lower sections A'and B or if so desired, this body gasket may be dispensed with.

Arranged in the float chamber 20 is a float 21 pivoted as at 28 for controlling a gasoline needle valve 29. The needle valve 29 co-acts with a seat 30 provided in the nipple 3| whereby a predetermined liquid level may be maintained in the float chamber 20. Secured to the lower end of'the nipple 3| as by a suitable packing nut 32 is a fuel feed pipe 33 and if so desired a suitable packing as at 34 may be provided for preventing leakage. The stem of the needle valve 29 preferably has its upper end arranged in a guide nut 35 threaded into the upper end of the extension 36.

The lower end of the idling fuel duct I9 is screw threaded for threaded reception of an idling tube '31 which projects downwardly into the float chamber 20 to a point preferably close adjacent the bottom of the chamber. The lower end of the tube 31 is provided with a small fuel opening 38 permitting but a small quantity of fuel to flow into the tube. Opening into the idling tube 31 at a point adjacent the top of the float chamber and above the normal liquid level in the chamber, is an air inlet 39 whereby fumes may be drawn from the upper portion of the float chamber into the idling tube. The float chamber 20 is provided adjacent its upper end with a suitable air vent 48 arranged above the normal liquid level in the chamber and at a point spaced from the idling tube 31. With this arrangement, air drawn thru the opening 48 will be allowed to mix with the fumes of the fuel before being drawn into the air inlet 39 of the idling tube.

Extending upwardly into the inner end of the main air intake 22 co-axial with the passage portion 2| is a vertical well casing 42 providing a well 43 having communication at its lower end with the float chamber 28 by the fuel passageway 44. The upper end of the well casing 42 is internally threaded for threaded reception of a mixing head 45 serving to close the upper end of the well 43. The mixing head 45 is preferably closed at its upper end by a'diifuser plate or head 46 provided with a suitable number of small openings as clearly shown in Figure 2. The upper end of the mixing head 45 terminates approximately on a level with the lower end of the Venturi tube 1, with the diameter of the-tubularshaped upper end of the mixing head considerably less than the internal diameter of the Venturi tube.

Secured either by threading or a pressed fit in the mixing head 45 is a nozzle 41 which co-acts with the diffuser plate 45 to provide a mixing chamber 48. The nozzle 41 is provided with a passageway 49 which is flared into conical shape at the lower end of the nozzle to provide a valve seat 50.

Threaded into the lower end of the well casing 42 is a needle valve fitting or nipple 5| forming a closure for the lower end of the well 43. The nipple 5| is internally screw threaded for receiving a combined high speed adjusting and air feed needle valve 52 having a tapered upper end for co-acting with the seat 50. The needle valve 52 is provided with an axial bore 53 providing an air inlet opening at the inner end of the needle valve directly below the opening 49 in the nozzle 41. A packing nut 54 is threaded upon the lower end of the nipple 5| and a suitable packing 55 is provided for preventing leakage past the needle valve. The upper end of the needle valve 52 extends above the normal liquid level in the float chamber 20 to prevent the fuel from escaping thru the air inlet 53.

It will be seen that the heating portion I2 is a solid. mass or body of metal substantially covering the whole of the float chamber 20. When this solid mass of metal |2 becomes heated from the heat of the engine with which the carburetor is associated, the; float chamber, as well as the fuel therein, will become heated so that the fuel will be easily vaporized. It will be observed that the float chamber and the fuel therein are not heated by any form of heating jacket or the like i but rather by conduction thru the transfer of heat from the solid metal portion l2.

In operation of the carburetor, when the throttle II is opened, and also the choke valve 23, air will be drawn in thru the main air intake 22 and pass upwardly thru and also about the Venturi tube 1. The passage of air upwardly thru the tube 1 will create a suction at the upper perforated end of the mixing head 45. This suction at the diffuser plate 46 will cause a quantity of the liquid fuel in the well 43 to be drawn thru the opening 49 in the nozzle 41 into the mixing chamber 48. At the same time, air will be drawn thru the axial bore 53 in the needle valve 52 and be directed thru the nozzle 41 into the mixing chamber 48. With-this arrangement, it will be seen that there is an initial mixing of the warm fuel and air in the mixing chamber 48 prior to passage ofthis mixture thru the diffuser plate 46 for mixture with the main or primary air supply entering at the intake 22. This causes a thorough and proper mixing of the fuel and air for the explosive charge to be drawn upwardly thru the passage 5.

When the throttle H is closed and the engine idling, an idling supply of fuel will be delivered thru the opening l5 into the passage 5. The suction created above the throttle l I will cause a very small quantity of the fuel in the float chamber 20 to be drawn into the idling tube 31 thru the small opening 38 at the lower end thereof. Fumes from the upper portion of the float chamber will also be drawn in thru the inlet 38 and pass upwardly thru the idling fuel duct I9 with the fuel drawn thru the opening 38 and into the idling mixing chamber l4. Air will also be drawn=into the idling mixing chamber l4 thru the air inlet formed axially thru the idling adjusting valves 6.

From the foregoing it will be seen that a carburetor of improved construction has been provided wherein there is an initial mixing of fuel and air prior to discharge of this mixture into the main air supply for the carburetor. A novel heating means is also provided in the form of a solid metal body of substantial volume forming a cover for the float chamber.

1' claim:

1. In a carburetor having a fuel delivery passage provided with a main air intake, a fuel well at the lower end of the passage, a mixing head closing the upper end of the well and providing a mixing chamber having discharge openings into the passage, a nozzle in said head, and a fuel adjusting and air feed needle valve for controlling fuel and air feed thru said nozzle to said mixing chamber.

2. In a carburetor having a fuel delivery passage provided with a main air intake, a fuel well casing at the lower end of the passage, a mixing head secured in the upper end of the casing and providing a mixing chamber having a diffuser head, a nozzle in said mixing head below the diffuser head, and a needle valve extending thru the well casing and co-acting with the nozzle for controlling communication between the interior of the well casing and the mixing chamber, said needle valve having an axial bore providing an air inlet to the mixing chamber.

3. A carburetor comprising upper and lower horizontally divided sections providing a vertical fuel delivery passage having a main air intake at its lower-end, means securing the sections together, a float chamber in the lower section and having its cover formed by a portion of the upper section, a main fuel mixing chamber in the lower portion of said passage, a fuel adjusting and air feed needle valve for the mixing chamber, an idling mixing chamber in the upper section, a fuel adjusting and air feed needle valve for the idling mixing chamber, an idling fuel passageway for the idling mixing chamber and an idling tube secured to the upper section in communication with the idling fuel passageway and extending downwardly into said float chamber, said idling tube having spaced openings arranged one above and the other below the normal liquid level in the float chamber.

CHARLES O. GROSZ. 

